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From 1b8d2789dad0005fd5e7d35dab26a8e1203fb6da Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt@redhat.com>
Date: Wed, 24 Nov 2021 12:07:39 -0500
Subject: [PATCH] dm btree remove: fix use after free in rebalance_children()
Git-commit: 1b8d2789dad0005fd5e7d35dab26a8e1203fb6da
Patch-mainline: v5.16-rc6
References: git-fixes

Move dm_tm_unlock() after dm_tm_dec().

Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/persistent-data/dm-btree-remove.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/persistent-data/dm-btree-remove.c b/drivers/md/persistent-data/dm-btree-remove.c
index 70532335c7c7..cb670f16e98e 100644
--- a/drivers/md/persistent-data/dm-btree-remove.c
+++ b/drivers/md/persistent-data/dm-btree-remove.c
@@ -423,9 +423,9 @@ static int rebalance_children(struct shadow_spine *s,
 
 		memcpy(n, dm_block_data(child),
 		       dm_bm_block_size(dm_tm_get_bm(info->tm)));
-		dm_tm_unlock(info->tm, child);
 
 		dm_tm_dec(info->tm, dm_block_location(child));
+		dm_tm_unlock(info->tm, child);
 		return 0;
 	}
 
-- 
2.35.3